cork oak Fagaceae Quercus suber L.   symbol: QUSU5
	Leaf: Alternate, simple, evergreen, leathery, ovate to elliptical, 2 to 3 inches long, margin either entire or usually with wavy teeth; leaf surface cupped, dark green above, very fuzzy and whitened below. Flower: Monoecious; males are slender, yellow-green catkins 2 to 3 inches long; females are very small, in clusters of 2 to 4 in leaf axils; both appear in early spring. Fruit: Acorn, 1 to 1 1/2 inches long, narrow, oblong; loose scaly cap covers approximately 1/2 of the nut; matures in 1 season. Twig: Moderate, light gray-brown, abundant gray fuzz; buds clustered, reddish brown, with some gray fuzz, broadly triangular and pointed. Bark: Very unique, light gray with deep reddish brown furrows, developing very thick (inches) layers of cork, ruggedly ridged and furrowed; reddish brown when recently harvested for cork. Form: A medium sized tree (up to 65 feet tall) typically with a low dividing trunk.
	USDA Plants Database Quercus suber is planted in the highlighted USDA hardiness zones to the left and is not known to widely escape cultivaton.